- Dehydrogenative Carbon-Carbon Bond Formation Using Alkynyloxy Moieties as Hydrogen-Accepting Directing Groups
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In the presence of a catalyst system consisting of Pd(OAc)2, PCy3, and Zn(OAc)2, the reaction of alkynyl aryl ethers with bicycloalkenes, α,ss-unsaturated esters, or heteroarenes results in the site-selective cleavage of two C-H bonds followed by the formation of C-C bonds. In all cases, the alkynyloxy group acts as a directing group for the activation of an ortho C-H bond and as a hydrogen acceptor, thus rendering the use of additives such as an oxidant or base unnecessary. Alkyne into alkene: A palladium catalyst enables dehydrogenative C-C bond-forming reactions between alkynyl aryl ethers and alkenes or heteroarenes. The presence of the alkynyloxy group is key for these transformations as it acts as a directing group for the site-selective cleavage of two C-H bonds as well as an acceptor for the released hydrogen.
- Minami, Yasunori,Kodama, Tatsuro,Hiyama, Tamejiro
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Read Online
- Gold(I)-Catalyzed Intramolecular Hydroarylation of Phenol-Derived Propiolates and Certain Related Ethers as a Route to Selectively Functionalized Coumarins and 2 H-Chromenes
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Methods are reported for the efficient assembly of a series of phenol-derived propiolates, including the parent system 56, and their Au(I)-catalyzed cyclization (intramolecular hydroarylation) to give the corresponding coumarins (e.g., 1). Simple syntheses of natural products such as ayapin (144) and scoparone (145) have been realized by such means, and the first of these subject to single-crystal X-ray analysis. A related process is described for the conversion of propargyl ethers such as 156 into the isomeric 2H-chromene precocene I (159), a naturally occurring inhibitor of juvenile hormone biosynthesis.
- Cervi, Aymeric,Vo, Yen,Chai, Christina L. L.,Banwell, Martin G.,Lan, Ping,Willis, Anthony C.
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p. 178 - 198
(2020/12/22)
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- Fe(III)-Catalyzed Decarboxylative C3-Difluoroarylmethylation of Coumarins with α,α-Difluoroarylacetic Acids
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A facile Fe(III)-catalyzed oxidative decarboxylative radical coupling reaction of α,α-difluoroarylacetic acids with coumarins has been developed. This transformation, which provides a series of C-3 difluoroarylmethylated coumarins containing various functional groups in moderate-to-good yields, features easily accessible starting materials and operational simplicity.
- Chen, Zhiwei,Bai, Xiang,Sun, Jie,Xu, Yicheng
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supporting information
p. 7674 - 7682
(2020/07/15)
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- Visible-light-induced regioselective alkylation of coumarins via decarboxylative coupling with N-hydroxyphthalimide esters
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An efficient photocatalytic decarboxylative 3-position alkylation of coumarins by using alkyl N-hydroxyphthalimide esters as alkylation reagents has been developed. A variety of NHP esters derived from aliphatic carboxylic acids (primary, secondary, and tertiary) has been proved to be tolerated for this decarboxylation process, affording a broad scope of 3-alkylated coumarin derivatives in moderate to excellent yields. This protocol was highlighted by its mild conditions, readily available starting materials, operational simplicity, and wide functional group tolerance.
- Jin, Can,Yan, Zhiyang,Sun, Bin,Yang, Jin
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supporting information
p. 2064 - 2068
(2019/04/11)
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- Iron-Catalyzed Regioselective Decarboxylative Alkylation of Coumarins and Chromones with Alkyl Diacyl Peroxides
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A facile iron-catalyzed decarboxylative radical coupling of alkyl diacyl peroxides with coumarins or chromones has been developed, affording a highly efficient approach to synthesize a variety of α-alkylated coumarins and β-alkylated chromones. The reaction proceeded smoothly without adding any ligand or additive and provided the corresponding products containing a wide scope of functional groups in moderate to excellent yields. This protocol was highlighted by its high regioselectivity, readily available starting materials, and operational simplicity.
- Jin, Can,Sun, Bin,Xu, Tengwei,Yan, Zhiyang,Zhang, Xun
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supporting information
p. 1585 - 1591
(2019/08/07)
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- Synthesis method for coumarins compound
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The invention discloses a synthesis method for a coumarins compound. The structural formula is shown in the specification, wherein R1 is selected from one or more of -H, -CH3, -OCH3, -F, -Cl, -Br, -OH, -NO2 and N(CH2CH3)2 and R2 is selected from one of -H, -CH3 or CH2CH3. According to the invention, a 2-hydroxy cinnamate compound is directly utilized as a raw material and the coumarins compound is synthesized in one step under the catalytic effect of visible light. Compared with the present synthesis method, the synthesis method for the coumarins compound disclosed by the invention has the characteristics of simple method, mild condition and high yield; the reaction is carried out under normal temperature; and the visible light is utilized as a reaction energy source and is green and pollution-free.
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Paragraph 0056; 0057; 0058; 0059; 0060; 0061; 0062; 0063
(2017/08/29)
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- Bichromatic Photosynthesis of Coumarins by UV Filter-Enabled Olefin Metathesis
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Herein, we report on a two-step bichromatic synthesis of coumarins involving UV-A and UV-C light. The first step is a UV-A-photoinduced ruthenium-catalyzed cross-metathesis (CM) reaction of 2-nitrobenzyl-protected 2-hydroxystyrenes with acrylates, using an external solution of 1-pyrenecarboxaldehyde as a UV filter. Irradiation in the absence of the filter permanently inhibits the light-activated catalyst due to photocleavage of the photolabile protecting group (PPG) and ensuing phenolate chelation to the ruthenium. The simple removal of the external filter after CM allows further photochemical reactions with UV-C light to achieve more complex architectures, such as the coumarins presented in this work. (Figure presented.).
- Eivgi, Or,Sutar, Revannath L.,Reany, Ofer,Lemcoff, N. Gabriel
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p. 2352 - 2357
(2017/07/22)
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- Synthetic method of 6-methylcoumarin
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The invention discloses a synthetic method of 6-methylcoumarin. The 6-methylcoumarin is synthesized through a one-step reaction of p-methyl phenol and ethyl formylacetate under the catalysis of phosphotungstic acid. Compared with the prior art, the method disclosed in the invention has the advantages of few synthesis steps and small environmental pollution.
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Paragraph 0011; 0012; 0017
(2016/11/14)
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- Metal-free, Br?nsted acid-mediated synthesis of coumarin derivatives from phenols and propiolic acids
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A novel synthesis of coumarin derivatives by Br?nsted acid-mediated condensation and intramolecular cyclization of phenols and propiolic acids was reported. This transformation requires the use of TfOH in place of a conventional metal mediator, and it occurs under mild conditions and provides rapid access to coumarin derivatives in good yields.
- Choi, Hyuck,Kim, Jaehyun,Lee, Kooyeon
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supporting information
p. 3600 - 3603
(2016/07/21)
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- Process for preparing coumarin derivatives using phenol and propiolic acid
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Provided is a manufacturing method of coumarin derivative. The manufacturing method of coumarin derivative comprises a step of making a phenol compound react with a propiolic acid compound. According to the present invention, the manufacturing method of coumarin derivative is quick and efficient, and is useful to fields requiring synthesis of coumarin derivatives of various structures.COPYRIGHT KIPO 2016
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Paragraph 0110; 0111
(2017/01/12)
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- ALDOSTERONE SYNTHASE INHIBITOR
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PROBLEM TO BE SOLVED: To provide a compound having aldosterone synthase inhibition effect useful for treatment of primary aldosteronism causing hypertension or hypokalemia by overproduction of aldosterone, and a pharmaceuticals containing the compound. SOLUTION: There are provided an imidazole compound including 4-[5-(2-fluoroethyl)-1H-imidazole-1-ylmethyl]-3-iodobenzonitrile, 1-(3-bromo-4-cyanobenzyl)-1H-imidazole-5-carboxylic acid methyl, 1-(2-iodo-4-nitrobenzyl)-1H-imidazole-5-carboxylic acid methyl, 1-(3,5-di-tert-butylphenyl)-1H-imidazole-5-carboxylic acid methyl, 1-(2H-chromene-2-on-6-ylmethyl)-1H-imidazole-5-carboxylic acid methyl and 1-(2H-chromene-2-on-6-ylmethyl)-5-iodo-1H-imidazole as examples, and pharmaceuticals containing the compound. COPYRIGHT: (C)2015,JPOandINPIT
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Paragraph 0016; 0061; 0062; 0096; 0097
(2018/10/10)
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- Cp?Co(III)-Catalyzed Annulations of 2-Alkenylphenols with CO: Mild Access to Coumarin Derivatives
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Cp?Co(III)-catalyzed annulations of 2-alkenylphenols with CO for the synthesis of coumarin derivatives have been developed. The reaction features mild reaction conditions, broad substrate scope, and good functional group tolerance. Preliminary mechanistic studies were conducted, suggesting that C-H activation is the turnover limiting step. Furthermore, the efficiency of this reaction was demonstrated by the rapid total synthesis of three natural products herniarin, xanthyletin, and seselin.
- Liu, Xu-Ge,Zhang, Shang-Shi,Jiang, Chun-Yong,Wu, Jia-Qiang,Li, Qingjiang,Wang, Honggen
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supporting information
p. 5404 - 5407
(2015/11/18)
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- An expeditious coumarin synthesis via a "Pseudocycloaddition" between salicylaldehydes and ketene
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A variety of salicylaldehydes effected tandem nucleophilic addition onto ketene, leading to corresponding coumarins in good yields under mild conditions. This "pseudocycloaddition" represents a very mild variant of the historic Perkin synthesis of coumarin (which remains of key interest in both perfumery and several emerging areas).
- Chandrasekhar, Sosale,Kumar, Honnaiah Vijay
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supporting information
p. 232 - 235
(2015/10/29)
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- A practical one-pot synthesis of coumarins in aqueous sodium bicarbonate via intramolecular Wittig reaction at room temperature
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An efficient, simple and relatively inexpensive method for the synthesis of coumarins in aqueous sodium bicarbonate at ambient temperature has been developed. It features an intramolecular Wittig reaction of substituted 2-formylphenyl 2-bromoacetate in saturated aqueous sodium bicarbonate. Its advantages include benign reaction conditions, easy work-up and good overall yield with short reaction time. Various substituted coumarins have been synthesized by utilizing this methodology. This journal is
- Belavagi, Ningaraddi S.,Deshapande, Narahari,Sunagar, Manjunath G.,Khazi, Imtiyaz Ahmed M.
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p. 39667 - 39671
(2014/12/11)
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- Palladium-catalyzed synthesis of benzofurans and coumarins from phenols and olefins
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Triple C-H functionalization: Palladium-catalyzed synthesis of benzofurans and coumarins by reacting phenols and unactivated olefins is described. The reaction comprises sequential C-H functionalization and shows diverse functional group compatibility. Preliminary mechanistic studies shed light into the possible mechanisms. Copyright
- Sharma, Upendra,Naveen, Togati,Maji, Arun,Manna, Srimanta,Maiti, Debabrata
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supporting information
p. 12669 - 12673
(2013/12/04)
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- Amine-catalyzed cascade synthesis of 3,4-diunsubstituted coumarins
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We disclose an efficient route to synthesize 3,4-diunsubstituted coumarins through a cascade organocatalytic reaction. The reaction is catalyzed by using of a combination of benzylamine (10 mol-%) and triethylamine (10 mol-%). Various salicylaldehydes were tested, and the corresponding coumarin products were obtained in good to high yields under mild and metal-free reaction conditions. We disclose an efficient route to synthesize 3,4-diunsubstituted coumarins through a cascade organocatalytic reaction. The reaction is catalyzed by using of a combination of benzylamine (10 mol-%) and triethylamine (10 mol-%). Various salicylaldehydes are tested, and the corresponding coumarin products are obtained in good to high yields under mild and metal-free reaction conditions. Copyright
- Wei, Jia,Wang, Pengcheng,Jia, Qianfa,Huang, Jiaoyao,Du, Zhiyun,Zhang, Kun,Wang, Jian
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supporting information
p. 4499 - 4502
(2013/07/26)
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- One-pot catalysis of dehydrogenation of cyclohexanones to phenols and oxidative Heck coupling: Expedient synthesis of coumarins
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One-pot reactions leading to highly functionalized coumarins have been developed via a Pd(ii)-catalyzed dehydrogenation-oxidative Heck-cyclization process.
- Kim, Donghee,Min, Minsik,Hong, Sungwoo
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supporting information
p. 4021 - 4023
(2013/07/26)
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- TMSOTf-catalyzed intramolecular seleno-arylation of tethered alkenes: A novel method for the solid-phase synthesis of dihydrocoumarins and coumarins
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TMSOTf-catalyzed intramolecular seleno-arylation of tethered alkenes was performed using polystyrene-supported succinimidyl selenide as the selenium source. This catalytic process provides an efficient method for the regioselective synthesis of dihydrocoumarins possessing a seleno-functionality, followed by traceless cleavage of selenium linker to provide dihydrocoumarins and coumarins in good yields and purities.
- Tang,Li, Wen,Gao, Zhang Yong,Gu, Xi
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experimental part
p. 631 - 634
(2012/07/03)
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- A single precatalyst tandem RCM-allylic oxidation sequence
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Ring closing metathesis of allyloxy styrenes and a subsequent Ru-catalyzed allylic oxidation can be combined to a tandem sequence that makes coumarins accessible using less active but more conveniently available first generation catalysts.
- Schmidt, Bernd,Krehl, Stefan
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supporting information; experimental part
p. 5879 - 5881
(2011/06/23)
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- Photocleavage of dimers of coumarin and 6-alkylcoumarins
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The cleavage of four coumarin dimers, the syn-head-to-tail (ht) dimer of parent coumarin (syn-ht-CC1), the anti- and syn-hh dimers of 6-methylcoumarin (anti-hh-CC2 and syn-hh-CC2, respectively) and the anti-hh dimer of 6-dodecylcoumarin (anti-hh-CC3), was studied by UV-vis and IR spectroscopy and HPLC upon direct 254nm irradiation as well as sensitized excitation. The quantum yield of dimer splitting is Φsp=0.1-0.3 in various solvents and the effects of structure and solvent polarity are small. In certain solvents some of the dimers produced CO2 along with the monomers in the splitting reaction. Electron transfer from dimers to the triplet state of sensitizers, such as benzophenone or 9,10-anthraquinone, was observed in acetonitrile.
- Wolff, Thomas,G?rner, Helmut
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scheme or table
p. 219 - 223
(2010/10/01)
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- The Au(I)-catalyzed intramolecular hydroarylation of terminal alkynes under mild conditions: Application to the synthesis of 2H-chromenes, coumarins, benzofurans, and dihydroquinolines
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(Chemical Equation Presented) Operationally simple Au(I)-catalyzed intramolecular hydroarylation (IMHA) reactions of terminal alkynes that proceed in high yield and under very mild conditions are described. These processes involve low catalyst loadings, mild reaction temperatures, and short reaction times, require no cocatalysts or additives, and allow for the generation of a number of important heterocyclic motifs from readily accessible starting materials.
- Menon, Rajeev S.,Findlay, Alison D.,Bissember, Alex C.,Banwell, Martin G.
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supporting information; experimental part
p. 8901 - 8903
(2010/03/01)
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- Synthesis of coumarins by Pt-catalyzed hydroarylation of propiolic acids with phenols
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Synthesis of coumarins from phenols and propiolic acids was examined by using a Pt catalyst such as PtCl2/AgOTf, K2PtCl4/AgOTf, and K2PtCl4/AgOAc. Propiolic acid reacted even with less reactive phenols in trifluoroacetic acid to give coumarins and dihydrocoumarins. In the case of substituted propiolic acids, phenylpropiolic acid and 2-octynoic acid, the reactions proceeded selectively to afford coumarins in good to high yields.
- Oyamada, Juzo,Kitamura, Tsugio
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p. 6918 - 6925
(2007/10/03)
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- Microwave-assisted solventless Pechmann condensation
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Solventless Pechmann condensation of various phenols with crotonic acid, malic acid, fumaric acid or maleic acid, using sulfuric acid or anhydrous zinc chloride under microwave irradiation yielded coumarins and chromanones.
- Helavi,Solabannavar,Salunkhe,Mane
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p. 279 - 280
(2007/10/03)
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- The effect of phenyl substituents on the release rates of esterase-sensitive coumarin-based prodrugs
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A coumarin-based prodrug system has been recently developed in our laboratory for the preparation of esterase-sensitive prodrugs of amines, peptides, and peptidomimetics. The drug release rates from this prodrug system were found to be dependent on the structural features of the drug moiety. In certain cases, the release can be undesirably slow for drugs that are secondary amines with relatively high pK(a)'s. Aimed at finding ways to manipulate the release rates to suit the need of different drugs, we have examined the effect of the phenyl ring substitutions on the release kinetics of such prodrugs and found that appropriately positioned alkyl substituents on the phenyl ring could help to facilitate the release by as much as 16-fold. Therefore, introduction of alkyl substituents on the phenyl ring should allow us to manipulate the release rates and, therefore, time profiles for different drugs.
- Liao,Hendrata,Sung Yong Bae,Wang
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p. 1138 - 1147
(2007/10/03)
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- Enolethers, XVIII. - A Simple Synthesis of Coumarins
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In boiling 1,2-dichloroethane 3-ethoxyacryloyl chloride (1) reacts with phenols 2 to yield 3-ethoxyacrylates 3, which by treatment with conc. sulfuric acid/10percent SO3 cyclize to give coumarins 9 in good yields.The methoxy-substituted compounds 3d and 3k do not react to coumarins 9 with H2SO4/SO3 but with POCl3/H2O at room temperature.
- Ziegler, Thomas,Moehler, Hans,Effenberger, Franz
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p. 373 - 378
(2007/10/02)
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- Selective ortho-Alkylation of Phenols with Sulphoxides via Sigmatropic Rearrangement: Synthesis of Coumarins
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ortho-Alkylphenols have been prepared from phenol and dialkyl sulphoxides via sigmatropic rearrangement, using thionyl chloride or phenyl chlorosulphinate as an activator of sulphoxides.In the same manner, ortho-phenylthiomethylphenol has been prepared in good yields.When ethyl phenyl sulphoxide, diallyl sulphoxide, and methyl methylsulphinylacetate were used as sulphoxides, none of the expected products were obtained.Salicylaldehyde has been prepared in moderate yield, when methyl methylthiomethyl sulphoxide was used as a sulphoxide. 3-(2-Hydroxyphenyl)propionic acid derivatives, which were obtained from substituted phenols and dimethyl 3,3'-sulphynyldipropionate, have been cyclized to give the corresponding coumarins in good yields.
- Sato, Kikumasa,Inoue, Seiichi,Ozawa, Kimio,Kobayashi, Tohru,Ota, Tomomi,Tazaki, Michiko
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p. 1753 - 1756
(2007/10/02)
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- A NEW COUMARIN SYNTHESIS BASED ON THE AROMATIC MATALATION REACTION
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A convenient synthetic approach to coumarins and polycyclic coumarins based on the aromatic metalation reaction is described.Several polycyclic coumarins exhibit strong anticarcinogenic activity.
- Harvey, Ronald G.,Cortez, Cecilia,Ananthanarayan, T.P.,Schmolka, Sanford
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p. 6137 - 6138
(2007/10/02)
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